Cengage Advantage Books: Sustaining the Earth 10th Edition by Tyler Miller,Scott Spoolman

تمرين 2

What major ecosystem and economic services do freshwater systems provide? What is a lake ? What four zones are found in most lakes? Distinguish between oligotrophic , eutrophic , hypereutrophic , and mesotrophic lakes. Define surface water , runoff , stream , and watershed ( drainage basin ). Describe the three zones that a stream passes through as it flows from mountains to the sea. Give three examples of inland wetlands and explain the ecological importance of such wetlands.